Rubber coating apparatus with excess rubber recovery mechanism

ABSTRACT

In rubber-coating apparatus including calender rollers which define a coating gap therebetween for applying rubber to a fabric web, and in which excess rubber accumulates outside the lateral edges of the web, a new type of excess rubber recovery apparatus includes a pair of excess rubber control bodies, each having the shape of a solid of revolution. Each of these bodies is suspended by a flexible rotary drive shaft from a drive unit connected by a universal joint to a carriage which is adjustable along a horizontal rail. The mechanism rotates the control bodies in a manner to displace the excess rubber toward the central region of the fabric and permit it to be conveyed back to the coating gap by one of the calender rollers.

2 Unite States [151 3,638,607

Jaffke 1 Feb. 1, 1972 [54] RUBBER COATING APPARATUS WITH 2,689,5459/1954 Nelson ..l18/249 X EXCESS RUBBER RECOVERY 2,789,530 4/1957Fleischauer..... M SM 3,104,182 9/1963 Schneider et al. ..118/261 X [72]Inventor: Heinz K. E. Jaifke, Adapazari, Turkey Primary ExaminerJamesKee Chi [73] Assignee: Uniroyal Endustri Turk, A.S., Adapazari, Atmmeywluard sprowls Turkey 57 ABSTRACT [22] Fllcd: 1969 In rubber-coatingapparatus including calender rollers which [21] Appl. No.: 848,508define a coating gap therebetween for applying rubber to a fabric web,and in which excess rubber accumulates outside the lateral edges of theweb, a new type of excess rubber [52] 11.8. C1 ..ll8/249, 118/261,118/262 recovery apparams includes a pair of excess rubber control Fieldof Search bodies, each having the shape of a solid of revolution. Eachof these bodies is suspended by a flexible rotary drive shaft from adrive unit connected by a universal joint to a carriage which [56]References cued is adjustable along a horizontal rail. The mechanismrotates the control bodies in a manner to displace the excess rubberUNITED STATES PATENTS toward the central region of the fabric and permitit to be congewen veyed back to the coating gap by one of the calenderrollers. rewsen 2,676,563 4/1954 Montgomery et al ..l18/249 X 11 Claims,1 Drawing Figure PATENTED-FEB 11972 $638.60?

INVENTOR.

RUBBER COATING APPARATUS WITH EXCESS RUBBER RECOVERY MECHANISM FIELD OFTHE INVENTION This invention relates generally to apparatus forrubbercoating fabrics, and is particularly concerned with means forrecovering excess rubber escaping from the edges of the coated fabric.

THE PRIOR ART Rubber-coated fabrics have a wide variety of uses. Anotable example is the manufacture of pneumatic tires for automotivevehicles, in which it is common for layers of such rubberized fabric tobe incorporated in the casing of the tire. In making rubberized fabricsfor this and other purposes, uncoated cord fabric is fed through acoating gap defined between a pair of calendar rollers, and a hot,pliable rubber mixture is fed through the gap at the same time, to bepressed into intimate relationship with the fabric by the pressure ofthe calendar rollers.

A difficulty encountered with this process is that the pressure exertedupon the pliable rubber material squeezes it out in a lateral directionrelative to the fabric web, forming lobes of excess rubber materialwhich extend beyond the lateral edges of the fabric. This excessmaterial is usually trimmed off and conveyed back over one of thecalender rollers to be returned to the entrance of the coating gap. Thispermits the excess rubber ultimately to be used for coating fabric,instead of being discarded as waste.

Recovery of the excess rubber in this manner presents certaindifficulties which the prior art has not been able to solve. The excessrubber lobes are quite thin and of a soft consistency, so that they aredifficult to handle. Yet for recovery purposes, the lobes must besevered from the lateral edges of the fabric and gathered toward thecentral region of the fabric, i.e., the region between the lateraledges, so that they can be added to the centrally located mass of rawrubber material waiting to enter the coating gap. Moreover, handling ofthe excess rubber in this manner must be done immediately as it emergesfrom the coating gap.

Prior art approaches to the problem of excess rubber recovery haveencountered a variety of difficulties. One such approach employs knifeedges to sever the excess rubber material from the lateral edges of thefabric, in conjunction with a mechanism for winding up the excess andintermittently returning it to the rubber stock at the entrance of thecoating gap. However, the use of knife edges to sever the excess has notbeen successful, primarily because the width of the fabric web issubject to some variation, resulting in a danger that the knife edgewill occasionally slice into the moving fabric. Another problem isencountered by the mechanism for winding up excess material, since thevelocity of the fabric web varies, which requires the winding speed tovary in :1 corresponding manner. This is difficult to accomplish becausethe tensile strength of the excess rubber material is low, and a simplecapstan type of windup mechanism which is overdriven through a slipclutch would simply pull the rubber apart. Finally, any approach whichreturns the excess rubber material to the coating stock only atintervals runs the risk that the excess material will be unsuitable forreturn to the coating stock without first undergoing reprocessing.

Another prior art approach applies a rubber coating only to one side ofthe fabric web, and controls the width of the excess rubber material sothat the lobe at each edge of the fabric has a width equal to about halfthe width of the web. Then these excess lobes are turned over andapplied to the opposite side of the fabric. The disadvantages of thismethod are that it requires a relatively wide set of calender rollers toaccommodate the larger lateral extent of the excess rubber lobes, plusthe fact the method is applicable only to a process in which the web iscoated successively on both sides.

Somewhat greater success has been achieved by severing the excess rubbermaterial in close proximity tothe calender rollers and taking advantageof the natural adhesiveness of the rubber material to convey it backover the surface of one of the rotating calender rollers for immediateredelivery to the entrance of the coating gap. With this approach, theoutermost longitudinal cords of the fabric web can conveniently serve ascutting edges against which the excess rubber material is severed, butsome form of stripping mechanism is required to cooperate with thesecords in the severing operation. The close proximity of the strippingmechanism to the calender rollers presents the danger that the highlypolished and vulnerable surfaces of these rollers will be damagedthrough contact. Even if one takes the precaution of forming thestripping mechanism of a softer material than the calender rollers, thisdanger is still present, because in prior art apparatus the strippingmechanism has a fixed position relative to the calender rollers. Otherconsequences which arise as a result of such a fixed position includewearing of the stripper mechanism, which necessitates intermittentadjustment and occasional replacement. Furthermore, any error in thepositioning of the stripper mechanism allows a quantity of the excessrubber to escape recovery, and some of the lost material clogs thebearings of the calender rollers, which increases the cost ofmaintenance of this type of equipment. Moreover the percentage of rubberwhich is recovered is unsatisfactory, and the material not automaticallyrecovered must be manually gathered at intervals, and reprocessed.

SUMMARY OF THE INVENTION The present invention solves these problems byproviding an excess rubber recovery mechanism comprising an excessrubber control body which has the shape of a solid of revolutionrelative to an axis, and means for rotating that body about its axis andmounting it in a position and attitude such that it contacts the excessrubber emanating from the edge of the fabric, and the rotation of thebody displaces the excess toward the central region of the fabric. Therotating and mounting means preferably comprises a drive unit and aflexible drive shaft connected to the excess rubber control body. Anadditional feature of the invention involves the suspension of the driveunit from an overhead support member, which may be a horizontal railalong which the drive unit is adjustable to accommodate difi'erentfabric widths. In a preferred embodiment of the invention, the driveunit is connected to an adjustable joint which permits a range ofadjustment of the attitude of the excess control body.

With this type of structure, the attitude and lateral position of theexcess control body are readily adjustable to accommodate differentwidths of fabric. The flexibility of the drive shaft permits the excesscontrol body to yield upon coming in contact with one of the calenderrollers, thus providing a dynamically self-adjusting system whichprecludes damage to the vulnerable polished surfaces of the calenderrollers. The rotational drive imparted to the excess rubber control bodyserves to strip the excess rubber material from the lateral edges of thefabric, as well as to gather it toward the central region of the fabricso that when it is conveyed back to the entrance of the coating gap bythe calender rollers it arrives at a proper position for subsequentreuse as fabric coating stock.

Additional advantages of the invention are that all of the excessmaterial is recovered, without loss of particles which might enter thebearings of the calender rollers, and it is no longer necessary toperform a special manual operation to collect unrecovered excessmaterial.

BRIEF DESCRIPTION OF THE DRAWING The single figure of the drawing is afront elevational view, partly diagrammatic in nature, of calenderapparatus for rubber-coating fabric, which includes an excess rubberrecovery mechanism in accordance with this invention.

DETAILED DESCRlPTlON OF THE PREFERRED EMBODIMENT The apparatusillustrated in the drawing includes a large stand 1 having a pair ofupright posts 1.1 and 1.1. between which metal calender rollers 2, 3 and4 are rotatably supported on respective shafts 2.1 and 2.1, 3.1 and 3.1,and 4.1 and 4.1. Calender rollers 3 and 4 are used to apply unvulcanizedrubber material to coat an elongated cord fabric web 13. This operationis accomplished within a coating gap 12 defined between the calenderrollers 3 and 4. The fabric web 13 proceeds through the gap 12 in aforward direction (i.e., upwardly out of the plane of the drawing,toward the reader,) while the pressure of calender rollers 3 and 4presses a'mass of hot, pliable rubber-coating stock 14 into surroundingrelationship with the cords of fabric 13 (including longitudinal cords13.2 in the central region of the fabric and outermost cords 13.1 and13.1 at the lateral edges thereof.) However, this pressure also has theeffect of forcing the rubber material laterally out beyond the edges ofthe fabric (i.e., beyond cords 13.1 and 13.1) to form excess rubberlobes 15 and 15 respectively.

For the purposes of illustration, the excess material 15 at theleft-hand side of the drawing is shown as though it had been severed atthe point where it emerges from the coating gap 12, while the excessrubber material 15 appearing at the right-hand side of the drawing isshown as it actually appears during a fabric-coating process performedby the apparatus of this invention. Specifically, the excess material 15at the right is torn upwardly from the fabric web 13 along a tear linedesignated 16 and, by virtue of the natural tendency of the rubbermaterial 15 to adhere to the rotating calender roller 3, it is conveyedupwardly over calender roller 3 to join a mass of feeding rubbermaterial 14'. The latter mass then passes through a gap 17 betweencalender rollers 2 and 3, and continues downwardly over the rear surfaceof rotating calender roller 3 until it returns to the entrance of thecoating gap 12 at the rear side of the calender rollers 3 and 4. In thisway the excess rubber material 15 is returned to the entrance of the gap12 for reuse as fabric coating stock.

The excess rubber material 15 separates from the edge of the fabric 13,by its natural adhesion to the calender roller 3, and is conveyed towardthe central region of the fabric 13 (i.e., intermediate the outermostcords 13.1 and 13.1,) by means of an excess rubber recovery mechanismfor the righthand edge of the fabric 13 which comprises a horizontalsupporting rail 5 projecting from upright post 1.1 of the supportingstand 1, and a suspension carriage 6 which is adjustable horizontallyalong the rail 5, a drive unit 8 which is suspended from the carriage 6by a universal joint 7, and an excess rubber-controlling body 11 whichis rotatably driven by, and suspended from, the drive unit 8, by meansofa drive shaft 10. A setscrew 9 releases the carriage 6 for horizontaladjustment along the rail 5, and then locks it in place relative to therail after the desired adjustment has been achieved, The drive unit 8 ispreferably a motor, for example a conventional electric motor, the speedof which can be controlled electrically from a remote location, togetherwith a suitable reduction gear in the output train. Alternatively, thedrive unit 8 may be a gear train or other rotary motion transmissionwhich is driven by a remotely located motor unit through appropriateflexible couplings. The drive shaft 10 is preferably a flexible cable ofconventional construction which suspends the body 11 in yieldablerelationship to the calender roller 3 and is driven by unit 8 to rotatethe excess rubber control body 11 in the angular direction indicated bythe arrow nearby.

In operation, the carriage 6 is properly positioned horizontally alongthe rail 5, and the universaljoint 7 is swiveled to the desired angle sothat the excess rubber control body 11 is suspended in contact with theexcess rubber lobe 15. By virtue of the adhesive relationship of thematerial 15 with the calender roller 3, the rotation of the calenderroller carries the material 15 upwardly around the front surface ofcalender roller 3 and toward the gap 17 between calender rollers 2 and3. In addition, the position of the carriage 6, and the angle of theuniversal joint 7, are selected so that the orientation of the excessrubber control body 11 is such that its rotational motion drives theexcess rubber material 15 from the right-hand edge (cord 13.1) of thefabric 13 toward the central region thereof (fabric cords 13.2.) As aresult, the excess rubber material 15 becomes folded over into narrowstrands 18 which are shifted inboard of the fabric 13 and join the mass14' centrally located at the entrance of the gap 17 between calenderrollers 2 and 3. This mass 14' is then conveyed through the gap 17 tothe rear of calender roller 3 (being flattened in the process) andpasses downwardly across the rear of that calender roller to enter thegap 12 from the rear side thereof for fabric coating purposes.

The body 1 1 has the shape of a solid of revolution; that is to say itis substantially cylindrical, and its axis of cylindrical symmetry iscoincident with the axis of drive shaft 10. However, the best resultsare obtained if the generally cylindrical shape of body 11 is modifiedby a slight crowning. Thus body 11 is slightly barrel shaped, with asomewhat larger diameter through its midsection 11.1 and a somewhatsmaller diameter at opposite ends 11.2. This helps the body 11 todisengage from the rubber material more readily after forming it intofolded strands 18.

Thus, the body 11, by virtue of its rotational movement and its positionand attitude relative to the excess rubber material 15 and calenderroller 3, serves under the rotation of the calender roller to convey thematerial around the calender roller into the feeding mass of rubber 14'.Moreover, the rotation of body 1 1 has the further effect of foldingover the excess rubber material into controlled, compact strands l8, andconveying these strands toward the center of the apparatus so that thefeeding mass 14' is centralized between the outermost fabric cords 13.1and 13.1. Consequently, as the feeding mass 14' passes through the gap17 and around the rear surface of the calender roller 3, it is properlypositioned so as to be usable for fabric-coating purposes.

The flexibility of the drive shaft 10 allows the excessrubbercontrolling body 11 to yield when it comes in contact with thecalender roller 3, a feature which prevents damage to the vulnerable,polished calender roller despite the close proximity which is necessarybetween the body 11 and the calender roller 3. In addition, therubber-controlling body 11 is preferably fabricated of a nonmetallicmaterial which is softer than the metal of the calender roller 3, forexample wood, plastic or the like, so as to ensure further againstscratching or other damage. The flexibility of the drive shaft 10 alsopermits the body 11 to accommodate itself to minor variations in thelateral width of the fabric 13.

At various times the speed with which material emerges from the coatinggap 12 may vary in accordance with process requirements. Therefore, itis preferable if the speed of the drive unit 8 is controllable to matchthe velocity of rotation of the excess rubber-controlling body 11 to thespeed of the excess rubber material 15. This is best accomplished by aremotely controlled electrical adjustment of the speed of the electricmotor of drive unit 8.

The excess rubber material 15 which extends beyond the outermost fabriccord 13.1 at the left-hand edge of the fabric has been removed forclarity of illustration, but it will be a preciated that this excessmaterial is also conveyed ever the calender roller 3 to form part of thefeeding mass 14'. For this purpose, there is provided a duplicate excessrubber recovery mechanism at the left, comprising a horizontal railing5', a suspension carriage 6, which is adjustable thereon and includes asetscrew 9' for locking purposes, a universal joint 7 which suspends adrive unit 8' from the carriage 6 and a flexible drive shaft 10' whichyieldably suspends an excess rubbercontrolling body 11' from the unit 8'and also drives it rotationally in the angular direction indicated bythe arrow nearby. Under the influence of this mechanism, the excessrubber material 15' proceeding upwardly along a tear line 16, under theoperation of this mechanism joins the feeding rubber mass 14 in the samemanner described for the right-hand excess material 15. The two driveunits 8 and 8 should preferably have a common speed control.

Thus it will be appreciated that this invention provides a novel excessrubber recovery mechanism for use in fabriccoating apparatus, whichreadily accommodates itself to different fabric widths and alsodynamically adjusts to minor variations in those widths. The mechanismfully recovers all excess rubber material which appears outside thelateral edges of the fabric, conveys it toward a central location, sothat it is conveyed back to the coating gap for reuse. The flexibilityof the drive shafts and the material of which the excessrubbercontrolling bodies are fabricated both militate against damage tothe polished surfaces of the calender rollers, while the crowned shapeof these bodies prevents them from becoming entangled in the recoveredrubber material. The 100 percent rubber recovery achieved by this deviceavoids clogging the calender roller bearings, and also avoids anynecessity for manual recovery ofa portion of the excess rubber material.

While there has been described what is at present considered to bepreferred embodiment of this invention, it will be obvious to thoseskilled in the art that. various changes and modifications may be madetherein without departing from the invention; and it is, therefore,intended to cover all such changes and modifications as fall within thetrue spirit and scope ofthe invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed, are defined as follows:

1. In rubber-coating apparatus including calender rollers which define agap therebetween for applying a rubber coating to a fabric web which hasopposite edges and a central region between said edges, and in which atleast one of said rollers conveys excess rubber, which accumulatesoutside the opposite edges of said web, back to said gap; an excessrubber recovery mechanism comprising:

at least one excess rubber control body having the shape of a solid ofrevolution about an axis;

and means for rotating said excess rubber control body about said axisand for mounting said body in a position and attitude such that saidbody contacts excess rubber extending beyond one of said fabric edgesand the rotation of said body displaces said excess rubber from said oneedge of said fabric toward the central portion of said gap by conveyingsaid excess rubber toward the center of the calender roller with whichit is in contact.

2. Apparatus as in claim 1, wherein:

said mounting means is flexible whereby to mount said excess rubbercontrol body for yielding movement upon coming in contact with saidcalender roller with which said excess rubber is in contact.

3. Apparatus as in claim 1, wherein said rotating and flexible mountingmeans comprises:

a flexible drive shaft connected for mounting and rotationally drivingsaid excess rubber control body;

and means for supporting and rotationally driving said drive shaft.

4. Apparatus as in claim 3, wherein:

said supporting means is located above said fabric web;

and said flexible drive shaft is arranged to suspend said body from saidsupporting means.

5. Apparatus as in claim 4 wherein:

said supporting and driving means includes a drive unit connected tosuspend and to rotationally drive said flexible drive shaft and asupport mechanism mounting said drive unit above said fabric web,whereby said flexible drive shaft suspends said excess rubber controlbody from said drive unit.

6. Apparatus as in claim 5, wherein:

said support mechanism comprises a substantially horizon tal rail and acarriage adjustable horizontally along said rail whereby to accommodatedifferent widths of fabric web;

said drive unit bein mounted on said carriage.

7. Apparatus as in c aim 6, further comprising:

means for releasably locking said carriage in a selected position alongsaid rail.

8. Apparatus as in claim 6, wherein:

said carriage comprises an adjustable joint connected to said drive unitand arranged for suspending said drive unit at any one ofa range ofangles.

9. Apparatus as in claim 1, wherein:

said excess rubber control body has a crowned shape.

10. Apparatus as in claim I, wherein:

said excess rubber control body is formed of a nonmetallic materialhaving a hardness substantially less than that of said calender rollerwith which said excess rubber is in contact.

11. Apparatus as in claim 1, wherein:

said rotating means is adjustable as to the speed at which it rotatessaid excess rubber control body.

2. Apparatus as in claim 1, wherein: said mounting means is flexible whereby to mount said excess rubber control body for yielding movement upon coming in contact with said calender roller with which said excess rubber is in contact.
 3. Apparatus as in claim 1, wherein said rotating and flexible mounting means comprises: a flexible drive shaft connected for mounting and rotationally driving said excess rubber control body; and means for supporting and rotationally driving said drive shaft.
 4. Apparatus as in claim 3, wherein: said supporting means is located above said fabric web; and said flexible drive shaft is arranged to suspend said body from said supporting means.
 5. Apparatus as in claim 4 wherein: said supporting and driving means includes a drive unit connected to suspend and to rotationally drive said flexible drive shaft and a support mechanism mounting said drive unit above said fabric web, whereby said flexible drive shaft suspends said excess rubber control body from said drive unit.
 6. Apparatus as in claim 5, wherein: said support mechanism comprises a substantially horizontal rail and a carriage adjustable horizontally along said rail whereby to accommodate different widths of fabric web; said drive unit being mounted on said carriage.
 7. Apparatus as in claim 6, further comprising: means for releasably locking said carriage in a selected position along said rail.
 8. Apparatus as in claim 6, wherein: said carriage comprises an adjustable joint connected to said drive unit and arranged for suspending said drive unit at any one of a range of angles.
 9. Apparatus as in claim 1, wherein: said excess rubber control body has a crowned shape.
 10. Apparatus as in claim 1, wherein: said excess rubber control body is formed of a nonmetallic material having a hardness substantially less than that of said calender roller with which said excess rubber is in contact.
 11. Apparatus as in claim 1, wherein: said rotating means is adjustable as to the speed at which it rotates said excess rubber control body. 